CN1739114A - Person recognition securement method and device - Google Patents

Abstract

The invention relates to person authentication systems. According to the invention, a chip card is provided with an integrated sensor for spectral information relating to the skin of the person holding the card between the thumb and the index finger. Spectral recognition uses electroluminescent diodes (12) and photodiodes (14) mounted on a flexible substrate comprising interconnection tracks between the electroluminescent diodes and photodiodes and a processor contained in the chip of the chip card.

Description

Personnel identification security method and device

technical field

The invention relates to a security device based on a chip card, which is suitable for applications requiring a high degree of security as a security measure against the risk of fraud.

Background technique

The chip card can be used to authenticate various operations through an authentication system included in its microprocessor. The most widely used technique for verifying that its holder is indeed its owner is through four-digit (PIN, or "Personal Identification Number") authentication. This technique offers the great advantage that it requires only a small amount of computing resources, since it only undertakes simple binary comparisons, and the encryption techniques for securing the exchange with the outside world have been known for a long time.

The biggest problem with protection based on four digits and by extension on any code is that it only discerns information known to the person (and, since the person is presenting the chip card, information he holds), not the person himself. Biometrics for identification by fingerprint, voice, face, iris recognition, etc. overcome this problem and make deception significantly more difficult because they are based on the identification of the person himself.

Biometric technology requires sensors for inputting biometric information (for example, a camera for inputting facial images), reference information stored in the memory of the chip card to avoid falsification, and a processor to compare the reference information with the input via the sensor. information for comparison.

It has been proposed to merge the sensors and all the computations directly on the chip card, but unfortunately there are several obstacles preventing this merger:

- The sensor is usually too thick for standard chip cards. For example, cameras require optics that are incompatible with the thickness of the card;

- sensors are often too large for chip cards: e.g. sensors that capture palm prints;

- Almost all biometric techniques require large computing power, which is incompatible with user acceptable latency. A waiting time of no more than a few seconds is important, but with the computing power available on the chip card, the calculations would take several minutes.

If the biometric sensor is placed on the chip card, it is important to be able to enter the biometric information when the card is inserted into the card reader, or before insertion, or with a contactless card, but this presents a serious power problem, because the card must be self-contained and thus have its own battery. For contactless cards employing energy delivered by radio frequency radiation, the power harvested by radiation is too weak for biometric sensors. There is therefore a need to use biometric technology that allows biometric information to be captured when the card is inserted.

To save storage space, the reference information stored on the card needs to be as small as possible. The space occupied by the PIN code is less than 4 bytes.

Ideally, the sensor should be able to detect forgery. For example, in the case of fingerprints, it is desirable to detect that the finger being probed is a live finger and not an amputated or fake finger.

A recognition technique based on the shape of the heart pulse has been proposed, but its performance (not as accurate as in the case of fingerprints) has not been proven, and so far has not been practically implemented.

Blood detection (pulse, hemoglobin oxygen content) through optical devices commonly used in medicine (infrared LED + photodiode of appropriate wavelength) seems to offer an interesting solution, but it can be deceived by a plastic material film placed on the finger, for Simple systems are even tricked by plastic materials that have the right color in infrared light. Also, it is important to wait for at least one full heartbeat, which is rather long for some athletic people and therefore not very convenient.

In US patent application 2002/0009213 a technique is proposed for the spectroscopic analysis of the skin, more specifically the dermis of certain parts of the body.

The technique involves illuminating the skin with several light-emitting diodes (LEDs) of different colors and analyzing the light transmitted by the skin at different distances. Using several photodiodes to measure a characteristic of the light: the farther the distance between the light emitter and the sensor, the greater the energy. Get deeper dermis properties. Furthermore, certain frequency bands (towards the infrared) are very sensitive to the presence of blood. The fact that photodiodes and LEDs must be assembled individually limits their number, so the associated costs add up very rapidly.

Contents of the invention

According to the invention, it is proposed to include a sensor on a chip card intended to be used in a conventional card reader for authenticating the person holding the card, the sensor being used to communicate with the person holding the chip card between his thumb and forefinger Spectral information about the skin.

Spectral recognition requires light-emitting diodes (LEDs) and photodiodes, which will be mounted individually (or in small groups) on flexible substrates to maintain the flexibility of the assembly. The substrate comprises, on the one hand, electrical lines providing the interconnection between the light-emitting diodes and the photodiodes, and, on the other hand, a processor contained in a chip of the smart card. The substrate is compatible with the packaging technology of the chip card, leaving the LEDs and photodiodes visible (or using a transparent material).

Spectral identification of the skin requires low computing power (an 8-bit processor is sufficient), and the size of the reference information is small: all compatible with currently employed technologies. Electronics for processing the spectral information to identify or identify a person will be contained in the chip card, and the card issues the identifying or distinguishing information.

Advantageously, both sides of the chip card are used to capture biometric information: this allows simultaneous measurement of the spectral properties of the thumb and forefinger, between which the card is held when inserted into a conventional chip card reader . This will make counterfeiting more difficult. Furthermore, in case of strong lighting, especially in the sun, at least one of the two sides (the bottom side facing the ground) will be in shadow and thus clearly operable.

If the card has its own energy source, it is possible to have the spectral information acquired just before the card is inserted into the reader. Advantageously, means are provided on the card for detecting that the card is held between the thumb and forefinger to initiate the acquisition of spectral information. If the cards do not have their own power source, the card reader must provide them with power.

A spectral band sensitive to hemoglobin in the infrared region is preferably used to confirm that the finger is alive. A heart pulse measurement could also be added to make the component more resistant to counterfeiting, as well as an oxyhemoglobin rate measurement. The user must then hold the card for at least the time required to complete the measurement, or two or three heartbeats.

The light emitting diodes needed to illuminate the skin can emit visible or near-infrared light at different wavelengths, preferably including wavelengths that lie in the absorption band of blood.

The authentication can be supplemented by other means, in particular by fingerprint recognition by means of a sensor which is also provided on the chip and arranged next to the spectral information acquisition device so as to be also under the finger when the card is held in the hand.

Description of drawings

Other features and advantages of the present invention will become clearer after reading the following detailed description with reference to the accompanying drawings, in which:

Figure 1 is a device according to the invention;

Fig. 2 is variation embodiment;

Fig. 3 is the processing step of chip card;

Figure 4 is the finished chip card.

Detailed ways

Figure 1 shows a chip card 10 of standard size, which is usually a few centimeters long and tens of millimeters thick, and which in practice is usually held between the thumb 30 and the forefinger of the person using the card in a card reader not shown. Between 40.

The card typically includes a silicon electronic chip 20 that performs a number of signal processing functions associated with the card reader; the electrical contacts are primarily located on the card for communication with the card reader; communication card, therefore the contact points are not shown in Figure 1.

Hold the card between your thumb and forefinger without the contact points to insert it into the card reader.

In Fig. 1, the side with the contact point is the right side of the figure, and the side on which the card is clamped is the left side. Visible markings are preferably provided on the card to indicate where the card must be held between the thumb and forefinger. According to the invention, in this position the chip card comprises means comprising a sensor for spectral information related to the skin of at least one of the two fingers gripping the card. The sensor actually comprises at least one light-emitting diode (LED) 12 that illuminates the finger and at least one photodiode 14 that provides an indication of the light received on the photodiode 14 from the LED 12 through the skin and after diffusion on the skin. to the electrical signal of the light part.

Preferably, the card comprises LEDs and photodiodes; the LEDs preferably emit light at multiple wavelengths so as to constitute a spectral pattern characteristic of the individual holding the card in his hand.

The LEDs and photodiodes needed to capture this spectral fringe are inserted into the thickness of the card. These electronic components are to be soldered or glued on the support, preferably flexibly and electrically interconnected by connecting wires to the chip 20 of the chip card: the chip is usually located in the chip card, at the contacts of the card when there are contact points directly above the point.

The card's electronic chip 20 includes a microprocessor for controlling the LEDs, reading the information sent by the photodiodes illuminated by the LEDs, analyzing the information and verifying the received spectral information with the pre-stored Computations required for matching between person-related spectrogram data.

Some calculations about the identification of persons can be performed outside the chip card, the card just sending data about the detected fingerprints. However, this solution is not very satisfactory from a security point of view.

A significant increase in the level of identification and security can be achieved by arranging LEDs and photodiodes on each side of the chip card. When the card is generally held between the thumb and forefinger, the spectral information can be read on each side, at least the shaded (lower) side in case of strong lighting.

Figure 2 shows the construction of a chip card in this case, with LEDs 12 and photodiodes 14 on the top side of the card and LEDs 12' and photodiodes 14' on the bottom side of the card.

In the case of Figures 1 and 2, the photodiode is implemented separately from the silicon chip, but it should be understood that since LEDs emit light at wavelengths that lie between the near-ultraviolet and near-infrared that silicon can detect, it is also possible to integrate the photodiode on the silicon chip. on chip. In this case, the chip is not located in the same position as the standard contact points of the chip, but in the position where the card is clamped. The chips are connected to the contacts (in the case of cards with contacts) by electrical connections embedded in the plastic material of the card.

The light emission of the LEDs is preferably in the red and near infrared, so that the light can penetrate well into the skin.

The actual acquisition of the spectrum of the skin consists in measuring the photoresponse of the skin to luminescent stimuli of different optical wavelengths. It is important to avoid measuring light reflected directly by the surface or superficial layer of the skin (stratum corneum). In fact, the information specific to each individual is located more in the dermal structure. It is therefore important for the light emitter (LED) to be spaced from the light sensor (photodiode) so that only light passing through the skin reaches the sensor, minimizing the portion of light coming directly from the LED or from the LED after a simple reflection on the skin . The choice of distance between the light emitter and detector can be used to limit the effect of direct reflections.

The LEDs are preferably controlled directly by using a silicon chip 20 which may contain all the electronic components needed to detect the fringe and detect spectral information.

People-recognition algorithms could also be incorporated on the silicon chip, which would make the system even cheaper. The algorithm is less about comparing the currently taking spectral measurement to a pre-stored set of spectral measurements with an individual (for simple comparison to check identity) or multiple individuals (for a simple comparison from several multiple comparisons that identify a person among individuals).

The technology can be used with LEDs positioned either above or below the card to double the measurement and thus increase identification performance, or, for example, with half the LEDs positioned above and the rest positioned below so that measurements are taken simultaneously to reduce readouts The time of the spectral pattern. Since the reading time is already very short, it is preferable to double the measurement to make the assembly more resistant to counterfeiting.

In order to check that the object being measured is indeed a live finger (not a fake latex finger, nor an amputated finger), preferably at least one measurement is made in the absorption band (infrared) of the blood, which is in the validation approval Measures with significant weights. At least one LED emitting at a wavelength lying in the absorption band of blood is used.

It is also possible to measure the pulse and the oxygen content in the blood, but this necessitates holding the card for several seconds (the time required to perform the measurement), which is not very convenient for use.

For example, spectral recognition performance is not as good as fingerprint recognition performance. In the case of chip cards, it is actually mainly concerned with authentication in verification mode, i.e., the purpose is simply to check the holder of the card, not to verify an individual out of several whose characteristics are stored in a database mode. This performance characteristic is sufficient for a general level of security, but if a higher level of security is required, other verification elements must be added.

Spectral fingerprints can be combined with fingerprints, and more specifically, with scanning techniques that yield high identification rates, or voice identification, or any other form of biometrics. Static or scan-based fingerprinting can use, inter alia, optical sensors, thermal sensors, capacitive sensors or pressure sensors. Additional authentication means are also preferably provided on the card, but signals originating from outside the card can also be used.

Fingerprints are preferred as an additional means of authentication, because since the finger is already in contact with the chip card, the capture of the fingerprint can be carried out simultaneously on the card, but this will require more computing resources and additional sensors, which (if necessary) words) may include photodiodes.

In order to implement the invention, a set of components related to spectral pattern acquisition, components related to additional biometric techniques and, in the case of a card with some independence, a battery can be assembled in a flexure comprising interconnection lines 60 between the components. On the supporting part (floral wire) 50. This flexible support is then sandwiched in the plastic material forming the chip card.

Figure 3 shows the support 50 (side view from the top), which has not yet been fitted between two sheets of protective plastic material.

FIG. 4 shows the completed chip card with external contact points 80 .

The different elements can be arranged to allow ultimate flexibility compatible with chip standards. In particular, they are not placed too close to each other. The LEDs 12 and photodiodes 14 will be arranged in a natural layout when gripped by two fingers.

In case an LED is to be used as a functional indicator for the user, for example to indicate that an operation has been completed correctly (green) or incorrectly (red), this LED will be located outside the card holding area. This LED and other appropriate indicator LEDS are controlled by the chip along with the personnel authentication operation.

Appropriate printed indicia can be provided on the card to show finger positioning and indicator LEDs.

Interconnects can be provided on both sides using vertical conductive via interconnects to connect top and bottom, or even connection points on the supporting wafer.

The two pieces of plastic material 65 and 70 to be glued to the support may have openings aligned with the LEDs and photodiodes so that they are subsequently filled with transparent material (glue, transparent resin) 75 .

A variation of this embodiment is to include the photodiode in the electronic chip, and place the chip under the location for the finger, next to the LED. This reduces the number of electronic components, thereby reducing costs.

Claims (15)

1. A chip card (10), characterized in that the chip card (10) comprises a sensor for spectral information related to the skin of the person holding the chip card between his thumb and forefinger, to identify The person holding the card. 2. The chip card as claimed in claim 1, characterized in that the sensor comprises at least one light-emitting diode (12) and at least one photodiode (14). 3. The chip card according to claim 2, characterized in that the light-emitting diodes and photodiodes are mounted on a flexible substrate (50), which on the one hand comprises a light-emitting diode and a photodiode The electrical interconnection (60) between and, on the other hand, the chip of the card. 4. The chip card as claimed in claim 3, characterized in that the flexible substrate is inserted between two sheets of plastic material, the transparent windows (75) being arranged on the one hand above the light-emitting diodes and on the other hand also above the photodiodes above. 5. The chip card as claimed in any one of claims 2 to 4, characterized in that the chip card comprises light-emitting diodes and photodiodes on either side of the card for the purpose of contacting the two fingers holding the card. Perform spectral identification. 6. The smart card as claimed in claim 2, characterized in that at least one light-emitting diode emits light in the absorption spectral band of blood. 7. The chip card according to any one of claims 2 to 6, characterized in that the chip card further comprises means for measuring the heart pulse and/or means for evaluating the rate of oxyhemoglobin to enhance the identification of persons. 8. The smart card as claimed in claim 2, characterized in that it comprises light-emitting diodes which emit light of different wavelengths. 9. The smart card as claimed in claim 1, characterized in that it comprises at least one photodiode contained in the chip. 10. A chip card as claimed in any one of claims 1 to 9, characterized in that the chip comprises electronics for processing spectral information from sensors for the authentication of the person holding the card. 11. A chip card as claimed in any one of claims 1 to 10, characterized in that the chip comprises a memory containing stored biometric data relating to the holder of the card. 12. The chip card as claimed in any one of claims 1 to 11, characterized in that the chip card further comprises means for detecting that the card is held between the thumb and forefinger to start acquiring spectral information by the sensor. 13. The chip card according to any one of the preceding claims, characterized in that it comprises other means for authenticating persons, in order to increase the security of the authentication process, which means are located on the card or use originating from the card. Information on the outside of the card. 14. The chip card as claimed in claim 13, characterized in that the additional authentication means is a static or scan-based fingerprint sensor, in particular an optical fingerprint sensor. 15. The chip card as claimed in any one of the preceding claims, characterized in that it comprises at least one light-emitting diode controlled by the chip to provide visual information relating to the authentication operation.

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